Databases
StackOverflow2013
Postsdbo
POWhy does BCrypt.net GenerateSalt(31) return straight away?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhy does BCrypt.net GenerateSalt(31) return straight away?
    primarykey
    data
    text
    <p>I stumbled across BCrypt.net after reading <a href="http://www.codinghorror.com/blog/archives/000953.html" rel="nofollow noreferrer">Jeff Atwood's post about storing passwords</a> which led me to Thomas Ptacek's recommendation to <a href="http://chargen.matasano.com/chargen/2007/9/7/enough-with-the-rainbow-tables-what-you-need-to-know-about-s.html" rel="nofollow noreferrer">use BCrypt</a> to store passwords. Which finally led me to <a href="http://derekslager.com/blog/posts/2007/10/bcrypt-dotnet-strong-password-hashing-for-dotnet-and-mono.ashx" rel="nofollow noreferrer">this C# implementation of BCrypt</a></p> <p>In the comments on the last link above someone asked "Why do GenerateSalt(30) take for ever, but GenerateSalt(31) seems to take no time at all?"</p> <p>I ran BCrypt.HashPassword(password, BCrypt.GenerateSalt(31)) and got my result in 0 milliseconds.</p> <p>I've been running BCrypt.HashPassword("password", BCrypt.GenerateSalt(30)) for over 5 minutes now and still do not have a result.</p> <p>I realize we'll probably not need a randomly generated 30 character salt to create our password hashes (or <a href="https://stackoverflow.com/questions/1561174/sha512-vs-blowfish-and-bcrypt#answer-1561245">irreversible encryption in BCrypt's case</a>) for years. <strong>EDIT</strong> I should have read the code a bit, logRounds doesn't have anything to do with the salt length. Thanks Aaronaught.</p> <p>So, why does GenerateSalt(31) return a value almost instantly (when it should take about twice as long as GenerateSalt(30)?</p> <p><strong>UPDATE</strong></p> <p>here is the fix:</p> <pre><code>private byte[] CryptRaw(byte[] password, byte[] salt, int logRounds) { // ... snip ... uint rounds = 1U &lt;&lt; logRounds; // ... snip } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USDavid Murdoch
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POWhy does BCrypt.net GenerateSalt(31) return straight away?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POWhy does BCrypt.net GenerateSalt(31) return straight away?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POWhy does BCrypt.net GenerateSalt(31) return straight away?
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload